[client] add gl-check script to check GL function calls

This prevents us from exceeding the minimum GL/EGL versions that we are
targetting or forced to use indirection for due to lack of guarantee in
the ABI.

gl-check

@@ -0,0 +1,152 @@
+#!/bin/bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname "${BASH_SOURCE[0]}")" &> /dev/null && pwd)"
+WAYLAND_SHELL="${WAYLAND_SHELL:-xdg-shell}"
+CLANG_QUERY="${CLANG_QUERY:-clang-query}"
+BUILD_DIR="${BUILD_DIR:-$SCRIPT_DIR/client/build}"
+
+case "$WAYLAND_SHELL" in
+  xdg-shell) shell_ignore=shell_libdecor.c ;;
+  libdecor)  shell_ignore=shell_xdg.c ;;
+  *)
+    echo "Unknown Wayland shell: $WAYLAND_SHELL"
+    exit 1
+esac
+
+if ! command -v "$CLANG_QUERY" &> /dev/null; then
+  echo "clang-query is not installed"
+  exit 1
+fi
+
+if [ ! -f "$BUILD_DIR/compile_commands.json" ]; then
+  echo "compile_commands.json not found in $BUILD_DIR"
+  echo 'Run cmake with -DCMAKE_EXPORT_COMPILE_COMMANDS=ON to enable'
+  exit 1
+fi
+
+tempdir="$(mktemp -d)"
+cleanup() {
+  rm -rf "$tempdir"
+}
+trap cleanup EXIT
+
+sed '/EGL_VERSION_1_5/,$d' /usr/include/EGL/egl.h > "$tempdir/egl1.4.h"
+
+getCalls() {
+  query="$1"
+  dir="$2"
+
+  command=(find "$dir" -name '*.c')
+  if [ $# -gt 2 ]; then
+    command+=(-not)
+    shift 2
+    for exclude in "$@"; do
+      command+=(-name "$exclude")
+    done
+  fi
+
+  cat > "$tempdir/query" <<EOF
+set output print
+set bind-root false
+m callExpr(callee(functionDecl(matchesName("::$query")).bind("func")))
+EOF
+
+  "${command[@]}" -exec "$CLANG_QUERY" -p "$BUILD_DIR/compile_commands.json" -f "$tempdir/query" {} + | \
+    grep -Po "(?<= )\b$query(?=\()" | sort -u
+}
+
+checkCalls() {
+  name="$1"
+  file="$2"
+  standard="$3"
+  while read -r func; do
+    if ! grep -q "$func" "$file"; then
+      echo "Found $func in $name, which is not in $standard"
+      fails=$((fails+1))
+    fi
+  done
+}
+
+getGLCalls() {
+  getCalls 'gl[A-WYZ]\w*' "$@"
+}
+
+getEGLCalls() {
+  getCalls 'egl[A-Z]\w*' "$@"
+}
+
+getGLXCalls() {
+  getCalls 'glX\w+' "$@"
+}
+
+checkGLESCalls() {
+  name="$1"
+  shift
+  checkCalls "$name" /usr/include/GLES3/gl3.h 'OpenGL ES 3.0' < <(getGLCalls "$@")
+}
+
+checkEGLCalls() {
+  name="$1"
+  shift
+  checkCalls "$name" "$tempdir/egl1.4.h" 'EGL 1.4' < <(getEGLCalls "$@")
+}
+
+checkGLCalls() {
+  name="$1"
+  shift
+  checkCalls "$name" /usr/include/GL/gl.h 'OpenGL 1.3' < <(getGLCalls "$@")
+}
+
+checkGLXCalls() {
+  name="$1"
+  shift
+  checkCalls "$name" /usr/include/GL/glx.h 'GLX 1.3' < <(getGLXCalls "$@")
+}
+
+forbidCalls() {
+  name="$1"
+  while read -r func; do
+    echo "Found $func in $name, which is forbidden"
+    fails=$((fails+1))
+  done
+}
+
+forbidEGLCalls() {
+  name="$1"
+  shift
+  forbidCalls "$name" < <(getEGLCalls "$@")
+}
+
+forbidGLXCalls() {
+  name="$1"
+  shift
+  forbidCalls "$name" < <(getGLXCalls "$@")
+}
+
+forbidGLCalls() {
+  name="$1"
+  shift
+  forbidCalls "$name" < <(getGLCalls "$@")
+}
+
+fails=0
+
+checkGLESCalls 'EGL backend'    client/renderers/EGL
+checkEGLCalls  'EGL backend'    client/renderers/EGL
+forbidGLXCalls 'EGL backend'    client/renderers/EGL
+checkGLCalls   'OpenGL backend' client/renderers/OpenGL
+forbidGLXCalls 'OpenGL backend' client/renderers/OpenGL
+
+checkGLXCalls  'X11 display server'     client/displayservers/X11
+forbidGLCalls  'X11 display server'     client/displayservers/X11
+checkEGLCalls  'Wayland display server' client/displayservers/Wayland "$shell_ignore"
+forbidGLCalls  'Wayland display server' client/displayservers/Wayland "$shell_ignore"
+forbidGLXCalls 'Wayland display server' client/displayservers/Wayland "$shell_ignore"
+
+if [ "$fails" -eq 0 ]; then
+  echo 'All GL function calls look fine.'
+else
+  echo 'Use indirection for the listed GL function calls.'
+  exit 1
+fi